const fp = require('lodash/fp')

const cars = [
    {
        name: 'Ferrari FF', horsepower: 660,
        dollar_value: 700000, in_stock: true
    },
    {
        name: 'Spyker C12 Zagato',
        horsepower: 650, dollar_value: 648000,
        in_stock: false
    },
    {
        name: 'Jaguar XKR-S', horsepower:
            550, dollar_value: 132000, in_stock:
            false
    },
    {
        name: 'Audi R8', horsepower: 525,
        dollar_value: 114200, in_stock: false
    },
    {
        name: 'Aston Martin One-77 ',
        horsepower: 750, dollar_value: 1850000,
        in_stock: true
    },
    {
        name: 'Pagani Huayra',
        horsepower: 700,
        dollar_value: 1300000,
        in_stock: false
    },
]
// let isLastlnStock = function (cars) {
//     //获取最后一条数据
//     let last_car = fp.last(cars)
//     //获取最后一条数据的 in_stock 属性值
//     return fp.prop('in_stock', last_car)
// }

//第一问
//用fp.flowRight改造上面得函数
let isLastlnStock1 = function (cars) {
    const result = fp.flowRight(fp.prop('in_stock'), fp.last)
    return result(cars)
}

//第二问
let isLastlnStock2 = function (cars) {
    const result = fp.flowRight(fp.prop('name'), fp.first)
    return result(cars)
}

//第三问
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length

}
let averageDollarValue = function (cars) {
    return _average(fp.map(car => car.dollar_value, cars))
}
//第四问
let sanitizeNames = (arr) => {
    let _underscore = fp.replace(/\W+/g, '_')
    const result = fp.flowRight(fp.toLower, _underscore)
    return result(arr)
}


console.log(isLastlnStock1(cars))
console.log(isLastlnStock2(cars))
console.log(averageDollarValue(cars))
console.log(sanitizeNames(['HELLO WORLD']))
